Affiliation: | 1. Department for Biophysical Chemistry, Institute of Physical and Theoretical Chemistry, Technical University of Braunschweig, 38106 Braunschweig, Germany Cluster of Excellence PhoenixD (Photonics, Optics and Engineering – Innovation Across Disciplines), 30167 Hannover, Germany;2. Department for Macromolecular Chemistry, Institute of Technical Chemistry, Technical University of Braunschweig, 38106 Braunschweig, Germany Cluster of Excellence PhoenixD (Photonics, Optics and Engineering – Innovation Across Disciplines), 30167 Hannover, Germany;3. Department for Biophysical Chemistry, Institute of Physical and Theoretical Chemistry, Technical University of Braunschweig, 38106 Braunschweig, Germany;4. Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, 30167 Hannover, Germany Cluster of Excellence PhoenixD (Photonics, Optics and Engineering – Innovation Across Disciplines), 30167 Hannover, Germany;5. Department for Macromolecular Chemistry, Institute of Technical Chemistry, Technical University of Braunschweig, 38106 Braunschweig, Germany;6. Department for Inorganic Solid-State and Materials Chemistry, Institute of Inorganic Chemistry, Leibniz University Hannover, 30167 Hannover, Germany Cluster of Excellence PhoenixD (Photonics, Optics and Engineering – Innovation Across Disciplines), 30167 Hannover, Germany;7. Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, 30167 Hannover, Germany |
Abstract: | Stable jet electrospinning (SJES) is a special form of optical fiber generation that prevents chaotic fiber whipping typical for conventional electrospinning procedures. Incorporation of highly emissive semiconductor nanoplatelets (NPLs) in such fibers has very high potential in optical data transmission, optological circuits, fiber lasers, solar light concentrators and many other fields because NPLs exhibit strongly directed emission from their surface plane due to various in-plane transition dipole moments. However, potential orientation control of 2D-NPLs in SJES is entirely unknown as electric fields and various mechanical forces contribute in a complex manner simultaneously. Here, the observation of counter-intuitive yet very beneficial orientation of rectangular CdSe/CdS 2D-NLP in SJES perpendicular to the fiber drawing axis is reported. Scanning electron microscopy, 3D-single particle excitation polarization microscopy, 3D-photogoniometry, polarized emission spectroscopy and small angle X-ray scattering (SAXS) demonstrate aggregation free perpendicular alignment of the NPLs in poly(methyl methacrylate) (PMMA) fibers, resulting in dominant emission in directions parallel to the fiber. It is suggested that the observed vertical alignment is due to normal forces resulting from viscoelastic expansion when the polymer solution leaves the cannula (Barus effect) and that using such perpendicular nano-emitter alignment forces allows for the generation of novel materials also beyond fibers. |